This big bore kit for 1986-'03 HD® Sportster® & Buell® Models increases the displacement of 883cc and 1200cc models to 79". The kit includes S&S 3-5/8" bore alumium cylinders, and forged 3-5/8" bore flat topped pistons with rings and wristpins, head gaskets, base gaskets, exhaust gaskets, and required hardware and instructions.
Crankcases must be bored to accept the larger 3-5/8" cylinders, and rebalancing of the stock flywheel assembly is highly recommended. Cylinders are stock length, so there are no chassis clearance issues, and stock length pushrods and manifolds may be used.
This kit has stock height cylinders and will fit Buell® motorcycles.
Compression ratio depends on cylinder head type used. If stock heads are used extensive cylinder head modifications must be performed,
making compression ratios completely dependent on final combustion chamber volume.